How can I hide my island in the 1600s?

Question

I have time traveled to the past on an oriental country in southeast Asia. I want to hide my island from European colonists using some technology available in both the future and the past.

Would building giant mirrors solve my problem? Thanks!

Answer 1

Publish the highest-quality maps for your area (Google maps.)

As more people see that your maps are the best, they will come to rely on them.

Obviously, leave your island out. Mark safe waterways far away. Leave some white, "unexplored" spots far away and hint that there might be valuable resources.

If you feel like it, mark your area as containing dangerous phenomena, like the Bermuda triangle.

Obviously, you'll have to sink the occasional ship that dares venture near your island. Do sink it. That will only heighten the perception of a "dangerous" area. (Well, it really is..)

Answer 2

Just loudly advertise that this island is the St Teresa's Benevolent Hospice for Sufferers of Leprosy and Syphilis. NO visitors allowed, but donations of food, clothing and money will be accepted.

You will enjoy your solitude in peace.

Answer 3

Shortly — don’t leave witnesses who have dared to approach your island.

There are 3 possibilities to make an island inaccessible, with 17th century tech:

1. in the 17th century they used compasses to navigate seas. If you place electric coils on your island, it might tamper with the north direction that compasses show. And it can allow ships to be misguided into dangers like rocks and so on. But it cannot prevent navigators using the sun and stars for plotting a path. 17th century navigators would probably be aware of a strange island that stops compasses working.

2. you can use 20-21th century surveillance drones and anti-naval artillery systems to simply sink approaching ships. No witnesses. People will know there is strange island where ships disappear, but nobody will dare to approach it.

3. you can use anti-ship mines, but it’s worth notice that 20th century mines used during WW2 were triggered by metal ship hulls, and 17th century ships were made of wood.

Answer 4

Sargasso.

Everybody thinks that it is an old myth that European sailors lived in dread of becoming mired for years in the vast shoals of sargasso that blocked the dead center of the sea. Little do they know the truth. Who would have thought that lunatics from the future were farming sargasso by the ton and weaving it together with tough plastic ties in a barrier completely surrounding their island?

Answer 5

Building giant mirrors won't help

There seem to be promising ways for optical trickery to help. See the following:

https://www.findlight.net/blog/2018/06/25/optical-cloaking/

It was just a quick search that shows optical cloaking. Seems promising right? Build gigantic mirrors all around the island that use this trick and presto! it's gone.

Unfortunately it's not as simple. In the article they are talking around the subject with "if you look head on to to wall" and "taking advantage of the focal lengths of a set of lenses". Each of these is directional and specific. You can't just place the mirrors or lenses all around the island and hope it works. Each is directional and making curved glass will make it much, much more difficult. If you manage it somehow you'll still be able to see some oddities, as whatever is behind it will be shown from the mirrors. If you'll be at an angle or at different distances, it often looks weird.

That is even under perfect conditions. What will happen at a beautiful sundown? Thanks to the large uniform rays you'll easily identify that the light was mirrored or bent at the island, making it stick out more. What about maintenance? The mirrors might deteriorate, or simply get wet or dirty. This will make it stand out again and make it a point of interest.

Mirroring or lensing anything will have a huge set of problems. You're better off killing/taking prisoner of the ships that land there and sent the empty ships back to sea/sink them along the coast. Stories, warnings and mystery will do the rest. Or just have it far away from the land, so most boats won't even try to cross that part of the ocean as their vessels aren't good enough to reach too far out onto sea. The chances of being discovered then are small.

You could even just put speakers all around the island with some lights in the trees. If colonists come close, activate some sinister music (they even had mass hysteria at one big musical piece in a concert hall one time as they weren't used to it!), some dangerous sounding/unknown sounds and a light show. Yes it might be known to the colonists, but no one will dare to get on the island.

Answer 6

South East Asia -Coastal Island? Or one of Indonesia or Philippines or that area?

You would also have to keep hidden from the Asians. News would spread.

Go inland. Some places deep in Papua New Guinea didn't have contact till WW2 (cargo cult) With current tech, easy to set up a base deep in the jungle of the one of the mountainous islands and fly in and out where you please. Some of the large islands like Java or Borneo or ones of the Philippines could have thousands of people hidden for hundreds of years.

Answer 7

Post Some Signs

A few leper colony signs would encourage ships to sail off elsewhere. A quick shamble along the beach wearing some rags for added. Some artistically posed skeletons in the jungle.

Any sort of disease threat would frighten off sailors. They will mark it on their maps and avoid the hell out of the place.

Answer 8

With 20th century technology, it is very simple:

• Keep some submarines patrolling your island and nearby waters.
• Use some radars or sonars to detect any approaching ship.
• Launch a torpedo against any ship that comes closer than, say, 300 km from your island.

Answer 9

Reefs. Far enough out they will stop any ship from sailing past and seeing your island. You will have to move a lot of mass, but you won't have to kill anyone, in case that helps.

Answer 10

You could create a constant hurricane around the island strong enough to keep 1600's ships at bay.

You would need to account for the fact that some ships may want to get in and out but as the scientific documentary Wonder Woman has shown, this is maybe not even needed.

Answer 11

Rename it to Iceland, Frozen wastes, or Here-Be-the-Kracken, something terrible sounding, so that people ignore it and won't want to go there.

Answer 12

Harpoons

Or, more specifically, a surface-launched Harpoon Block II+ ER Anti-Ship Missile

You can hide your island pretty well if you turn any wooden ships and their sailors into a pink mist when they get too close. You'll be able to sink them well before they get into visual range of your island, rumours of a cursed section of sea will spread when ships don't return, and there won't be anyone to tell the tale of why.

Answer 13

There are some good answers here: What natural phenomena could make an island unreachable?

Given this is the age of sail, why not go for putting the island deep in the "doldrums".

Answer 14

Maybe you could spread fear by poisoning people with radiation, poisonous gas or powders if they get too close to the island.

Combine this with maps marking the area as dangerous or cursed and magnets which make compasses go haywire for full effect.

You could make them feel sick, get burn-leisions on the skin, vomit, hallucinate and even pass out. On leaving the area (depending on how long they stayed) they could fully recover and confirm to others the area is a no-go.

I suppose there's nothing stopping you from mining radioactive materials like Polonium and a poisonous gas like natural gas or some chemical reaction bi product gas in the 17th century. Certainly Arsenic concoctions were easily obtainable in the 17th century.

(Just something related I found on Wikipedia...)

Leonardo da Vinci proposed the use of a powder of sulfide, arsenic and verdigris in the 15th century:

throw poison in the form of powder upon galleys. Chalk, fine sulfide of arsenic, and powdered verdegris may be thrown among enemy ships by means of small mangonels, and all those who, as they breathe, inhale the powder into their lungs will become asphyxiated.

It is unknown whether this powder was ever actually used.

Answer 15

Nuclear weaponry

I am quite sure that people in 1600s (maybe even until late 1800s) will NOT attempt another voyage or exploration to an island that retaliates with tactical nuclear missiles within some range.

Imagine an entire fleet of ships wiped out violently in a giant magic fireball, followed with a ripple of tsunami-like waves afterwards. A giant mushroom-shaped hot smoke that rise hundreds of meters high. Such things will frighten nearby observers that happen to be within line of sight. Survivors of such explosion (if any exists) or people near enough will develop weird diseases due to radiation. "What is this sorcery? What is this curse? Is this the work of that fireball?"

Scared of such cursed area in the ocean, explorers will perhaps not try to get too close. Haunted and terrified? Yes. Curious? Maybe. Willing to risk certain and utter destruction? Definitely not.

Missiles that are launched high to the air and strike back down is a majestically terrifying thing for the explorers to behold, while underwater torpedo is a stealthily mysterious one. Either option is okay.

tldr: Bermuda triangle, but nuclear weapons.

Cartography

I take the main inspiration from this answer. Publish best maps for your surrounding realm using data that is available in 21st century. People will eventually rely on your high quality, detailed, and very accurate maps. You can then work from there to hide, exclude, spread rumors, etc etc to minimize explorations. There are few tips, some from linked answer/comments, that you can use to remove your island from the map:

• Plainly just exclude your island. Replace it with just the blue oceans.
• Hide your island under/near the compass rose, i.e. the sign that says "NORTH THIS WAY".
• Hide your island under/near markers with very large fonts, e.g. "Indian Ocean" or "South China Sea". Put your island underneath, or if you feel creative, inside the letters "e" or "a" or "O".
• Hide your island under an inset map. It is usually assumed that inset maps are drawn over an area with nothing of interest, so no one thinks it's something worth to see/get to. Additionally, make the inset map a red herring, detailing other islands! (As an interesting side note, Northwest Angle becomes practically a US exclave in Canada because early border treaty draws inset map over its location, while not knowing what actual geographical landscape lies underneath.)
• Plainly mark seas surrounding your islands as "cursed" or "not for exploration" - or whatever language works best with the European explorers, complete with a tale about "people in the past" that came close and wiped out in giant magic fireball with radiation diseases. Bonus: if the island is luckily close enough to a civilization for it to witness, even only one curious voyage's tragedy will be enough to make rumors naturally develop among the peoples and confirm the "cursed" and "not for exploration" tag on the maps.

tldr Make really good maps and mislead people using them.

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In hindsight, I just realized this answer has a prior assumption that you are trying to hide a comparably small island, not a Southeast Asian island with the size of Java or Mindanao.

Answer 16

just make a rumor about your island that people die here be ready if someone comes there did not walk back alive. So the rumor will become true. And also use todays technology to tackle any stealth invasions. Also what you can do never ever make anyone mark your island Just make it a sea. or water like Bermuda triangle . It would be a long term strategy and work.

Answer 17

Tunnels

Low tech but effective. Build whatever infrastructure you want underground on an island without any interesting resources or supplies.

If anybody approaches, spot them with your advanced surveillance technology and retreat to the base until they sail off. If they prove persistent or are unable to get away (castaways) then break out the chloroform while they are sleeping.

Answer 18

What's yours is mine, and mine what's yours

Surround your island at a distance in a network of naval mines. Primitive sea mines were documented in China as far back as the 14th century, and the English used naval mines in the siege of La Rochelle in 1627. Sailors of that time would have at least heard about mines and the massive damage that they can do.

Your island will appear on maps, but the area around it will be marked as an active minefield. History books will tell stories of a conquered Chinese warlord who was banished to a inhospitable wilderness island, and kept imprisoned there by an impenetrable wall of the same sea mines that he used to torment his enemies. Minesweepers won't be developed for a very long time, so any remotely sane sailor would stay far away from the minefield.

Historical records of the island all say that it has no real value or resources of interest, especially not worth getting blown up over. Nobody has been dumb brave enough to verify those records, so you should be able to stay isolated in peace for quite a while. The notations on maps are accurate, so they won't draw any suspicion.

Answer 19

A film projector to scare them

(not an idea of mine, the Beagle Boys already had it).

Everybody knows that sailors are very superstitious, so you could use a film projector to cast some footage of monsters or ghosts on the cliffs or on some well-placed big blankets. This should be enough to frighten the sailors and keep them at distance.

In orderd to keep the ships far, you could also use the same idea with some of your ships. You make them sail in the night and when you notice any foreign ships moving too close to the island, you project some scary footage on their sails. Ilarity ensues

To add to this, you can

• pay some people to tell frightening stories about the island in the taverns of the ports nearby
• fly a swarm of drones in the night. They should have some faint light and stay at a fixed positions around the island: the sailors would see some never seen before stars, which would confuse and scare them.

Answer 20

If you don't mind being distant from south east Asia, but within easy reach you could consider:

• Norfolk Island, off the east coast of Australia. Uninhabited when the British rediscovered it in 1770 (Captain Cook). It was occupied in March 1788 & turned into a penal settlement.
• Lord Howe Island, off the east coast of Australia. Uninhabited when the British discovered it in 1788 while en-route to Norfolk Island.
• Montebello Islands, of the coast of Western Australia. It is close to Jakarta, or as it was in the 1600s, Batavia in the Dutch East Indies. Similarly for nearby Barrow Island. Any islands north of Geraldton (latitude 28° 46 'S), in Western Australia, the Dutch would most likely have known about.
• Rottnest Island might be a possibility. It was too far south for the Dutch to be interest in. It was uninhabited when Europeans rediscovered it in the 1600s. Nearby there are also Carnac & Garden Islands.